<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://unpkg.com/vue@next"></script>
</head>

<body>
    <div id="app"></div>
</body>
<script>
    let vm = {
        template: `
                    <div>{{count}}{{countAddFive}}{{countAddTen}}</div>
                `,
        setup () {
            const { ref, computed } = Vue
            let count = ref(0)
            let countAddFive = computed(() => {
                return count.value + 5
            })
            let countAddTen = computed({
                get: () => count.value + 10,
                set: (newValue) => { count.value = newValue - 10 }
            })
            setTimeout(() => { count.value++ }, 1000)
            return { count, countAddFive, countAddTen }

        }
    }
    let app = Vue.createApp(vm)
    app.mount('#app')
</script>

</html>